1. Field of the Invention
The present invention relates to the field of cell cultures and more particularly to the use of thermosetting plastics materials for improving supports used for cell growth.
2. Description of the Prior Art
It is known that cell cultures are generally produced either in monolayers on supports in the presence of liquid nutrient media, or in suspension in liquid nutrient medium, or in the presence of a semi-solid nutrient medium (agarose).
Suitable supports for cell growth are particularly neutral glass or plastics, generally based on polystyrene, which have undergone special treatment to render them suitable for cell growth. These plastics are for a single use end are sterilized by a physical treatment with the exclusion of heat. Recently, the use has commenced, for cell cultures of microsupports based on glass, polysaccharides ("Sephadex") or of plastics materials.
The supports for cell cultures must be of such a nature that the cells adhere easily thereto; they must not be toxic for the cells nor inhibit their growth. In addition, they must permit microscopic observations to be carried out easily.
As regards microsupports, tests have been carried out with glass beads or polystyrene beads; however these microsupports are not satisfactory for obtaining cultures on an industrial scale or are only satisfactory under certain conditions.
In this connection, reference may be made to the article of A. L. Van Wezel entitled "Microcarrier Cultures of Animal Cells" in the treaties "Tissue Culture Methods and Application" edited by Paul F. KRUSE JR and M. K. PATTERSON JR Academic Press New York and London 1973. It is, for example, indicated that cells do not adhere in a sufficiently fast manner to plastics beads, such as polystyrene beads or beads of "Rilsan", trademark for a polyamide also knows as nylon 11, which beads have undergone special treatment. On the other hand, it is pointed out that tests have been carried with "Spherosil" beads, "Spherosil" being the tradename for microbeads made of silica; these beads do not seem suitable for industrial cultures considering the relatively high density of these beads in the culture media. It is noted also that the various types of ion exchange resins comprised of dextran chains cross-linked to form a tridimensional matrice of polysaccharide and having diethylamino functional groups, known under the commercial name "DEAE-Sephadex" and available from PHARMACIA FINE CHEMICALS AB, UPPSALA, SWEDEN, do not all have the same properties as supports for cell cultures.
To improve the properties of "DEAE-Sephadex A 50" beads, it has already been proposed to coat them with nitrocellulose (see the article of A. L. Van Wezel mentioned above).